The present invention relates to a process for preparing an olefin polymer and a catalyst for the polymerization of an olefin. More specifically, the present invention relates to a process for efficiently preparing a homopolymer of an olefin having heretofore unknown characteristics or a copolymer of two or more kinds of olefins by the use of a transition metal complex compound having a specific constrained geometric structure as one of catalytic components, and a catalyst for the polymerization of the olefin.
Heretofore, it has been known that in a process for preparing an olefin polymer, a transition metal complex compound having a specific constrained geometric structure is used as a catalytic component. For example, Japanese Patent Application Laid-open No. 163088/1991 discloses a method for preparing an olefin polymer in the presence of a catalyst system comprising the combination of a titanium series transition metal compound as a main catalytic component and methyl aluminoxane as a cocatalyst. In this method, however, a large amount of expensive methyl aluminoxane must be used in an aluminum/titanium atomic ratio of 20 to 1000 in order to obtain a sufficient catalytic activity, and so the disclosed method has a drawback that the increase in a catalyst cost is inevitable.
Furthermore, Japanese Patent Application Laid-open No. 139504/1991 discloses a method for preparing an olefin polymer in the presence of a catalyst system comprising the combination of, for example, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentaidenyl)silanetitaniumdimethyl (hereinafter referred to as xe2x80x9cM-[alkyl] complexxe2x80x9d) and an ionic complex. This M-[alkyl] complex can usually be prepared from a halogen-substituted compound, for example, (t-butylamindo)dimethyl(tetramethyl-xcex75-cyclopentaidenyl)silanetitanium dichloride, but its manufacturing process is intricate and a reaction yield is low. In consequence, a manufacturing cost increases, and for this reason, the method is not practical. In addition, the method has a disadvantage that a sufficient activity cannot be exerted.
Moreover, in World open Publication WO 94/07927 (published on Apr. 14, 1994), there has been described the improvement of the productivity of an olefin polymer by the use of a catalyst system comprising a compound having a cyclopentadienyl group and a metal in the group 4 of the periodic table, an anion of a Brxc3x8nsted acid and an organic compound of an element in the group 13 of the same.
Under such circumstances, the present invention has been intended, and an object of the present invention is to provide a process for efficiently preparing a homopolymer of an olefin having heretofore unknown characteristics or a copolymer of two or more kinds of olefins by the use of an inexpensive and highly active catalyst containing, as one catalytic component, a transition metal complex compound having a specific constrained geometric structure. Another object of the present invention is to provide the catalyst for the polymerization of the olefin polymer.
The present inventors have intensively researched with the intention of achieving the above-mentioned objects, and as a result, it has been found that when one or more kinds olefin monomers are polymerized in the presence of catalytic components, i.e., an organic aluminum compound and at least one selected from a transition metal complex compound having a specific structure, an ionic compound capable of reacting with the transition metal complex compound or its derivative to form an ionic complex and a Lewis acid, an olefin polymer can efficiently be obtained, and the molecular weight of this polymer can be regulated under the control of the deterioration of activity and the expansion of a molecular weight distribution of the polymer which has been impossible by conventional techniques, and this polymer can possess the molecular weight distribution having less low-molecular weight and high-molecular weight portions and can have an optional molecular weight. In consequence, the present invention has been completed on the basis of this knowledge.
That is to say, the present invention is directed to a process for preparing an olefin polymer which comprises the step of polymerizing at least one olefin monomer in the presence of (A) a transition metal complex compound represented by the general formula (I) 
wherein M is a metallic element in the groups 3 to 10 of the periodic table or a metallic element in a lanthanoide series; L is a xcfx80-bonding ligand; A is a divalent group containing an element selected from elements in the groups 13, 14, 15 and 16 of the periodic table; B is a bonding group containing an element selected from elements in the groups 14, 15 and 16 of the periodic table, and A and B may optionally form a ring together; X is a "sgr"-bonding ligand, a chelating ligand or a Lewis base; and n is an integer of 0 to 6 which varies with the valence of M, and when n is 2 or more, a plurality of Xs may be the same or different, (B) at least one selected from a Lewis acid and an ionic compound capable of reacting with the transition metal complex compound of the component (A) or its derivative to form an ionic complex, and (C) an organic aluminum compound as catalytic components; and a catalyst for the polymerization of an olefin which comprises the above-mentioned catalytic components (A), (B) and (C).
In the present invention, a transition metal complex compound represented by the general formula (I) 
is used as a catalytic component (A).
In the general formula (I), M is a metallic element in the groups 3 to 10 of the periodic table or a metallic element in a lanthanoide series. L is a xcfx80-bonding ligand, and typical examples of this ligand include an allyl group, cyclopentadienyl groups, substituted cyclopentadienyl groups, cyclopentadienyl groups each having a hetero-atom in a cyclopentadienyl ring, and their substituted cyclopentadienyl groups. A is a divalent group containing an element selected from elements in the groups 13, 14, 15 and 16 of the periodic table, and B is a bonding group containing an element selected from elements in the groups 14, 15 and 16 of the periodic table. The above-mentioned A and B may optionally form a ring together.
Furthermore, X is a "sgr"-bonding ligand, a chelating ligand or a Lewis base, and examples thereof include a hydrogen atom, halogen atoms, organic metalloid groups, alkoxy groups, amino groups, hydrocarbon groups, hetero-atom-containing hydrocarbon groups, amido groups and carboxyl groups.
In the present invention, as the above-mentioned X, there is preferably used HX in which a pKa value is 23 or less, particularly a value in the range of 12 to xe2x88x9210. If the pKa value is more than 23, a manufacturing process is intricate and so a manufacturing cost increases. Typical examples of the preferable X include halogen atoms such as a chlorine atom and a bromine atom, carboxyl groups, sulfonyl groups, thioalkoxy groups, thioaryloxy groups, acetylacetonato groups, acetylacetate groups and malonate groups of the above-mentioned examples. The halogen atom is particularly preferable because of a low manufacturing cost (with regard to the pKa value, refer to xe2x80x9cADVANCED ORGANIC CHEMISTRY: REACTIONS, MECHANISMS, AND STRUCTURExe2x80x9d, Second edition, Jerry March, INTERNATIONAL STUDENT EDITION).
In the general formula, n is an integer of 0 to 6 which varies with the valence of M, and n is preferably in the range of 0 to 4, because the compound in which n is in such a range can be manufactured at a low cost. If n is 2 or more, a plurality of Xs may be the same or different.
In the present invention, preferable examples of the transition metal complex compound represented by the general formula (I) which can be used as the component (A) include (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium dichloride, (t-butylamido)dimethyl-(tetramethyl-xcex75-cyclopentadienyl)silanetitanium dibromide, (t-benzylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanetitanium difluoride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanezirconium dichloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanezirconium dibromide, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanezirconium difluoride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanetitanium dihydride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium chlorohydride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanetitaniumdimethyl, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitaniummethyl chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitaniumdiethyl, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium diisopropoxide, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitaniumdi(orthodimethylamino)benzyl, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium (III) (orthodimethylamino)benzyl, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitaniumdi(N-methyl-N-phenylamine, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium(orthodimethylamino)benzyl chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium (III) chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetantalum dichloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanetantalum trichloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanevanadium chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanelanthanum chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silaneyttrium chloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silaneneodymium chloride, (t-butylamido)(tetramethyl-xcex75-cyclopentadienyl) -1,2-ethanediyltitanium dichloride, (methylamido)(tetramethyl-xcex75-cyclopentadienyl)-1,2-ethanediyltitanium dichloride, (ethylamido)(tetramethyl-xcex75-cyclopentadienyl)-1,2-ethanediyltitanium dichloride, (t-buylamido)(tetramethyl-xcex75-cyclopentadienyl)methyl-enetitanium dichloride, (ethylamido)(tetramethyl-xcex75-cyclopentadienyl)methylenetitanium dichloride, (benzylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium dichloride, (phenyl phosphide)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanezirconium dichloride, (t-butylamido)dimethyl(indenyl)silanetitanium dichloride, (t-butylamido)dimethyl(1-phosphor-2,3,4,5-tetramethylcyclopentadienyl)silanetitanium dichloride, (t-butylamido)dimethyl(1-phosphor-3,4-diphenylcyclopentadienyl)-silanetitanium dichloride, (t-butylamido)dimethyl(3-phosphaindenyl)silanetitanium dichloride and (t-butylamido)dimethyl(1-bora-2,3,4,5-tetramethylcyclopentadiphenyl)silanetitanium dichloride.
Of these compounds, halogen-substituted compounds such as (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium dichloride, (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)silanetitanium dibromide and (t-butylamido)dimethyl(tetramethyl-xcex75-cyclopentadienyl)-silanetitanium(III) chloride are preferable.
In the present invention, when such a halogen-substituted compound as mentioned above is used, this halogen-substituted compound can be alkylated with the organic aluminum compound in the catalyst system to exert a catalytic activity, as described hereinafter. Therefore, the halogen-substituted compound can directly be used in a polymerization reaction, whereby a catalyst preparation step can be simplified and the manufacturing efficiency of the polymer can also be improved. Of the halogen-substituted compounds, the chlorine-substituted compound are preferable, because they are particularly easily alkylated with the organic aluminum compound.
In the present invention, the above-mentioned transition metal complex compounds which can be used as the catalytic component (A) may be used singly or in a combination of two or more thereof.
In the present invention, as a catalytic component (B), there can be used an ionic compound (B-1) capable of reacting with the transition metal complex compound of the component (A) or its derivative to form an ionic complex, and/or a Lewis acid (B-2).
As the component (B-1), any ionic compound can be used, so far as it is capable of reacting with the transition metal complex compound of the component (A) or its derivative to form an ionic complex, but from the viewpoints of productivity and stability, compounds represented by the following general formulae (II) and (III) can suitably be used:
([L1xe2x88x92R1]k+)p([Z]xe2x88x92)qxe2x80x83xe2x80x83(II)
([L2]k+)p([Z]xe2x88x92)qxe2x80x83xe2x80x83(III)
(wherein L2 is M2, R2R3M3, R43C or R5M3).
[in the formulae (II) and (III), [Z]xe2x88x92 is a non-ligand anion [Z1]xe2x88x92 or [Z2]xe2x88x92, and here [Z1]xe2x88x92 is an anion in which a plurality of groups are bonded to an element, i.e., [M1Y1Y2 . . . Yn]xe2x88x92 (wherein M1 is an element in the groups 5 to 15 of the periodic table, preferably an element in the groups 13 to 15 of the periodic table. Y1xe2x88x92Yn are each a hydrogen atom, a halogen atom, an organic metalloid group, an amino group, an alkoxy group, a hydrocarbon group or a hetero-atom-containing hydrocarbon group. Two or more of Y1xe2x88x92Yn may form a ring n is an integer of [(a valence of the central metal M1)+1]), and [Z2]xe2x88x92 is a Brxc3x8nsted acid alone in which an acidity constant (pKa) is xe2x88x9210 or less, a conjugate base of a combination of the Brxc3x8nsted acid and a Lewis acid, or a conjugate base which is usually defined as an ultra-strong acid. The group [Z2]xe2x88x92 may be coordinated by the Lewis base. Furthermore, L1 is a Lewis base, and R1 is a hydrogen atom or a hydrocarbon group, and R2 and R3 are each a cyclopentadienyl group or a substituted cyclopentadienyl group. The respective cyclopentadienyl groups may be the same or different, and two or more cyclopentadienyl groups may form a crosslinking structure. R4 is a hydrocarbon group, a hetero-atom-including hydrocarbon group or an alkoxy group, and R5 is a porphyrin, a phthalocyanine or an allyl derivative. k is an ion valence of [L1xe2x88x92Rl] or [L2] and it is an integer of 1 to 3, and p is an integer of 1 or more, and q=(pxk). M2 contains an element in the groups 1 to 3, 11 to 13 and 17 of the periodic table, and M3 is an element in the groups 7 to 12 of the periodic table].
In the anion [Z1]xe2x88x92 in which a plurality of groups are bonded to an element, i.e., [M1Y1Y2 . . . Yn]xe2x88x92, typical examples of M1 include B, Al, Si, P, As and Sb, and B and Al are preferable. Furthermore, typical examples of Y1, Y2 . . . Yn include amino groups such as a dimethylamino group and a diethylamino group, alkoxy groups and aryloxy groups such as a methoxy group, an ethoxy group, an n-butoxy group and a phenoxy group, hydrocarbon groups such as a methyl group, an ethyl group an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-octyl group, an n-eicosyl group, a phenyl group, a p-tolyl group, a benzyl group, a 4-t-butylphenyl group and a 3,5-dimethylphenyl group, halogen atoms such as fluorine, chlorine, bromine and iodine, hetero-atom-including hydrocarbon groups such as a p-fluorophenyl group, a 3,5-difluorophenyl group, a pentachlorophenyl group, a 3,4,5-trifluorophenyl group, a pentafluorophenyl group, a 3,5-bis(trifluoromethyl)phenyl group and a bis(trimethylsilyl)methyl group, organic metalloid groups such as a pentamethylantimony group, a trimethylsilyl group, a trimethylgermil group, a diphenylarsine group, a dicyclohexylantimony group and a diphenylboron. Typical examples of the non-ligand anion, i.e., the Brxc3x8nsted acid alone in which the acidity constant (pKa) is xe2x88x9210 or less, or the conjugate base [Z2]xe2x88x92 comprising the combination of the Brxc3x8nsted acid and the Lewis acid include a trifluoromethanesulfonic acid anion (CF3SO3)xe2x88x92, a bis(trifluoromethanesulfonyl)methyl anion, a bis(trifluoromethanesulfonyl)benzyl anion, a bis(trifluoromethanesulfonyl)-amide, a perchloric acid anion (ClO4)xe2x88x92, a trifluoroacetic acid anion (CF3CO2)xe2x88x92, a hexafluoroantimony anion (SbF6)xe2x88x92, a fluorosulfonic acid anion (FSO3)xe2x88x92, a chlorosulfonic acid anion (ClSO3)xe2x88x92, a fluorosulfonic acid anion-5-antimony fluoride (FSO3-SbF5)xe2x88x92, a fluorosulfonic acid anion-5-arsenic fluoride (FSO3-ASF5)- and a trifluoromethanesulfonic acid-5-antimony fluoride (CF3SO3-SbF5)xe2x88x92.
Moreover, typical examples of L1 include ammonia, amines such as methylamine, aniline, dimethylamine, diethylamine, N-methylaniline, diphenylamine, N,N-dimethylaniline, trimethylamine, triethylamine, tri-n-butylamine, methyldiphenylamine, pyridine, p-bromo-N,N-dimethylaniline and p-nitro-N,N-dimethylaniline, phosphines such as triethylphosphine, triphenylphosphine and diphenylphosphine, ethers such as dimethyl ether, diethyl ether, dioxane and tetrahydrofuran, a thioether such as tetrahydrothiophene, an ester such as ethyl benzoate, nitriles such as acetonitrile and benzonitrile, straight-chain unsaturated hydrocarbons such as ethylene, butadiene, 1-pentene, isoprene and their derivatives, and cyclic unsaturated hydrocarbons such as benzene, toluene, xylene, cyclooctadiene and cyclooctatetraene.
Typical examples of R1 include hydrogen, a methyl group, an ethyl group, a benzyl group and a trityl group, and typical examples of R2 and R3 include a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group and a pentamethylcyclopentadienyl group. Typical examples of R4 include a phenyl group, a p-tolyl group and a p-methoxyphenyl group, and typical examples of R5 include a tetraphenylporphyrin, phthalocyanine, allyl and methallyl. In addition, typical examples of M2 include Li, Na, K, Ag, Cu, Br, I and I3, and typical examples of M3 include Mn, Fe, Co, Ni and Zn.
Typical examples of the ionic compound capable of reacting with the transition metal compound or its derivative of the above-mentioned component (A) to form an ionic complex, i.e., the (B-1) component compound include triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, methyl(tri-n-butyl)-ammonium tetraphenylborate, benzyl(tri-n-butyl)ammonium tetraphenylborate, dimethyldiphenylammonium tetraphenylborate, triphenyl(methyl)ammonium tetraphenylborate, trimethylanilinium tetraphenylborate, methylpyridinium tetraphenylborate, benzylpyridinium tetraphenylborate, methyl(2-cyanopyridinium) tetraphenylborate, triethylammonium tetrakis(pentafluorophenyl)borate, tri-n-butylammonium tetrakis-(pentafluorophenyl)borate, triphenylammonium tetrakis(pentafluorophenyl)borate, tetra-n-butylammonium tetrakis(pentafluorophenyl)borate, tetraethylammonium tetrakis(pentafluorophenyl)borate, benzyl(tri-n-butyl)ammonium tetrakis(pentafluorophenyl)borate, methyldiphenylammonium tetrakis(pentafluorophenyl)borate, triphenyl(methyl)ammonium tetrakis(pentafluorophenyl)borate, methylanilinium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis-(pentafluorophenyl)borate, trimethylanilinium tetrakis-(pentafluorophenyl)borate, methylpyridinium tetrakis(pentafluorophenyl)borate, benzylpyridinium tetrakis(pentafluorophenyl)borate, methyl(2-cyanopyridinium) tetrakis(pentafluorophenyl)borate, benzyl(2-cyanopyridinium) tetrakis(pentafluorophenyl)borate, methyl(4-cyanopyridinium) tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis[bis(3,5-ditrifluoromethyl)phenyl]borate, ferrocenium tetraphenylborate, silver tetraphenylborate, trityl tetraphenylborate, tetraphenylporphyrinmanganese tetraphenylborate, ferrocenium tetrakis(pentafluorophenyl)borate, (1,1xe2x80x2-dimethylferrocenium) tetrakis(pentafluorophenyl)-borate, decamethylferrocenium tetrakis(pentafluorophenyl)-borate, silver tetrakis(pentafluorophenyl)borate, trityl tetrakis(pentafluorophenyl)borate, lithium tetrakis(pentafluorophenyl)borate, sodium tetrakis(pentafluorophenyl)-borate, tetraphenylporphyrinmanganese tetrakis(pentafluorophenyl)borate, silver tetrafluoroborate, silver hexafluorophosphate, silver hexafluoroarsenate, silver perchlorinate, silver trifluoroacetate and silver trifluoromethanesulfonate.
From the viewpoints of productivity and stability, preferable examples of these enumerated compounds include triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, methyl(tri-n-butyl)ammonium tetraphenylborate, benzyl(tri-n-butyl)-ammonium tetraphenylborate, dimethyldiphenylammonium tetraphenylborate, triphenyl(methyl)ammonium tetraphenylborate, trimethylanilinium tetraphenylborate, methylpyridinium tetraphenylborate, benzylpyridinium tetraphenylborate, methyl(2-cyanopyridinium) tetraphenylborate, triethylammonium tetrakis(pentafluorophenyl)borate, tri-n-butylammonium tetrakis(pentafluorophenyl)borate, triphenylammonium tetrakis(pentafluorophenyl)borate, tetra-n-butylammonium tetrakis(pentafluorophenyl)borate, tetraethylammonium tetrakis-(pentafluorophenyl)borate, benzyl(tri-n-butyl)ammonium tetrakis(pentafluorophenyl)borate, methyldiphenylammonium tetrakis(pentafluorophenyl)borate, triphenyl(methyl)ammonium tetrakis(pentafluorophenyl)borate, methylanilinium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis(pentafluorophenyl)borate, trimethylanilinium tetrakis-(pentafluorophenyl)borate, methylpyridinium tetrakis(pentafluorophenyl)borate, benzylpyridinium tetrakis(pentafluorophenyl)borate, methyl(2-cyanopyridinium) tetrakis(pentafluorophenyl)borate, benzyl(2-cyanopyridinium) tetrakis(pentafluorophenyl)borate, methyl(4-cyanopyridinium) tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, dimethylanilinium tetrakis[bis(3,5-ditrifluoromethyl)phenyl]borate and trityl tetrakis(pentafluorophenyl)borate.
The ionic compounds, which are the (B-1) components, capable of reacting with the transition metal compound or its derivative of the above-mentioned component (A) to form an ionic complex may be used singly or in a combination of two or more thereof.
A use ratio of the catalytic component (A) to the catalytic component (B-1) in the present invention is suitably in the range of 20:1 to 1:20, more preferably 2:1 to 1:2 in terms of a molar ratio. The use ratio within the above-mentioned range is preferable for the sake of a low catalyst cost and a high polymerization activity.
On the other hand, no particular restriction is put on the Lewis acid which is the component (B-2), and this Lewis acid may be an organic compound or a solid inorganic compound. As the organic compound, boron compounds, aluminum compounds and the like are preferably used, and as the inorganic compound, magnesium compounds and the like are preferably used. Examples of the aluminum compounds include bis(2,6-di-t-butyl-4-methylphenoxy)aluminum methyl and (1,1-bi-2-naphthoxy)aluminum methyl, examples of the magnesium compounds include magnesium chloride and diethoxymagnesium, and examples of the boron compounds include triphenylboron, tris(pentafluorophenyl)boron, tris[3,5-bis(trifluoromethyl)phenyl]boron, tris[(4-fluoromethyl)phenyl]boron, trimethylboron, triethylboron, tri-n-butylboron, tris(fluoromethyl)boron, tris(pentafluoroethyl)boron, tris(nonafluorobutyl)boron, tris(2,4,6-trifluorophenyl)boron, tris(3,5-difluoro)boron, tris[3,5-bis(trifluoromethyl)phenyl]boron, bis(pentafluorophenyl)-fluoroboron, diphenylfluoroboron, bis(pentafluorophenyl)-chloroboron, dimethylfluoroboron, diethylfluoroboron, di-n-butylfluoroboron, pentafluorophenyldifluoroboron, phenyldifluoroboron, pentafluorophenyldichloroboron, methyldifluoroboron, ethyldifluoroboron and n-butyldifluoroboron.
These Lewis acids may be used singly or in a combination of two or more thereof.
A use ratio of the catalytic component (A) to the catalytic component (B-2) is preferably in the range of 1:0.1 to 1:2000, more preferably 1:0.2 to 1:1000, most preferably 1:0.5 to 1:200 in terms of a molar ratio, and this use ratio can suitably be selected in compliance with the kind of Lewis acid. The use ratio within the above-mentioned range is preferable for the sake of a low catalyst cost and a high polymerization activity.
The components (B-1) and (B-2) which are the catalytic components (B) may be used singly or in combination.
In the present invention, an organic aluminum compound is used as a catalytic component (C), and as this organic aluminum compound, there can usually be used a compound represented by the general formula (IV)
R6rAlQ3-r . . . xe2x80x83xe2x80x83(IV)
(wherein R6 is an alkyl group having 1 to 12 carbon atoms; Q is a hydrogen atom, an alkoxy group having 1 to 20 carbon atoms or a halogen atom; and r is an integer of 1 to 3).
Typical examples of the compound represented by the general formula (IV) include trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri(2-methylpentyl)aluminum, tri-n-octylaluminum, tri-n-decylaluminum, triphenylaluminum, methyldiisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, ethylisobutylaluminum chloride, diisobutylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, isobutylaluminum dichloride, diethylaluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride and ethylaluminum sesquichloride.
As described below, the organic aluminum compound can exert various functions in the present invention, but in any case, in order to efficiently carry out the under-mentioned alkylation, it is preferable to use a hydrocarbon group-containing aluminum compound having at least one hydrocarbon group of 3 or more carbon atoms, preferably 3 to 10 carbon atoms. From the viewpoints of catalytic activity and molecular weight distribution adjustment, triisobutylaluminum is particularly preferable.
A use ratio of the organic aluminum of the catalytic component (C) to the catalytic component (A) is preferably 30 or more, more preferably 200 or more, most preferably in the range of 200:2500 in terms of an aluminum/transition metal element ratio.
When the use ratio is in the above-mentioned range, the polymerization activity per the transition metal can noticeably be improved. However, if the use ratio is more than the above-mentioned range, the organic aluminum compound is used in vain and remains in large quantities in the polymer unpreferably. Conversely, if it is less than the above-mentioned range, the improvement effect of the polymerization activity is low.
In the polymerization reaction of the present invention, the organic aluminum compound can exert the following functions. In the first place, the employment of the organic aluminum compound as the component (C) permits obtaining the catalyst for polymerization having a much higher catalyst function efficiency than a catalyst for polymerization comprising the catalytic components (A) and (B).
The molecular weight of the polymer can be controlled by using two or more kinds of hydrocarbon group-containing aluminum compounds having at least one hydrocarbon group of 1 or more carbon atoms as the organic aluminum compound which is the catalytic component (C). The two or more kinds of organic aluminum compounds may be used simultaneously or stepwise. By simultaneously feeding the two or more kinds of organic aluminum compounds, the molecular weight can be adjusted under the inhibition of the deterioration of the catalytic activity and the increase in the molecular weight. On the other hand, by stepwise feeding the two or more kinds of organic aluminum compounds, the polymer having the molecular weight distribution in which low-molecular weight and high-molecular weight portions are suppressed can be obtained. As such two kinds of organic aluminum compounds, a combination of triisobutylaluminum and trimethylaluminum or triethylaluminum can preferably be used. No particular restriction is put on a use ratio of the two or more kinds of organic aluminum compounds, and the polymers having various molecular weights and molecular weight distributions can be obtained by changing a mixing ratio or a use ratio of the organic aluminum compounds.
Furthermore, when at least one kind of higher olefin monomer (e.g., 1-butene, 1-hexene or 1-octene) as a comonomer is polymerized with a lower olefin monomer (e.g., ethylene or propylene) by using two or more kinds of hydrocarbon group-containing aluminum compounds having at least one hydrocarbon group of 1 or more carbon atoms in the same manner as described above, a copolymer having an extremely high comonomer content can be obtained which has not heretofore been acquired by a Ziegler-Natta catalyst. Also in this case, the content of the comonomer which is the higher xcex1-olefin can be adjusted by changing the mixing ratio or the use ratio of the two or more kinds of organic aluminum compounds. As a typical use example, it is desirable to use triisobutylaluminum and another organic aluminum compound in a molar ratio of 1000:1 to 1:1000, preferably 100:1 to 1:100. If the mixing ratio is present in this range, a particularly excellent molecular weight adjusting function can be obtained.
In the present invention, the organic aluminum compound also functions as an alkylating agent, in the case that a halogen-substituted compound is used as the component (A). This function permits the halogen-substituted compound to be directly used as the component (A) in the polymerization reaction, by which a catalyst preparation step can be simplified. Heretofore, even if the halogen-substituted compound is directly used as the catalytic component, the catalytic activity has never or scarcely been obtained. Therefore, via a step in which a halogen in the halogen-substituted compound is replaced with another substituent, the thus treated compound has been added to the catalyst system. For example, a dichloro-substituted compound has been alkylated to be converted into a dimethyl compound, prior to its use as the catalytic component. In this case, the yield of the dimethylation has been about 56%. In view of such a conventional procedure, the effect of the present invention that the alkylation step is not required is large from the viewpoint of the simplification of the catalyst preparation step. That is to say, in the present invention, since the organic aluminum compound also functions as an alkylating agent for the halogen-substituted compound, the halogen-substituted compound is alkylated in the catalyst system to exert the catalytic activity. In consideration of such a fact, the alkyl group-containing aluminum compounds having at least one alkyl group of 3 or more carbon atoms, preferably 3 to 10 carbon atoms are preferable, and triisobutylaluminum is particularly preferable.
In the present invention, at least one of the catalytic components, when used, can be supported onto a suitable carrier. No particular restriction is put on the kind of carrier, and inorganic oxide carriers, other inorganic carriers and organic carriers can all be used. However, from the viewpoint of the easiness of morphology control and handling, the inorganic oxide carriers and the other inorganic carriers are particularly preferable.
Typical examples of the inorganic oxide carriers include SiO2, Al2O3, MgO, ZrO2, TiO2, Fe2O3, B2O3, CaO, ZnO, BaO, ThO2 and mixtures thereof, for example, silica-alumina, zeolite, ferrite, glass fiber and smectites. Above all, SiO2 and Al203 are particularly preferable. In this connection, the above-mentioned inorganic oxide carrier may contain a small amount of a carbonate, a nitrate, a sulfate or the like.
On the other hand, examples of the carriers other than mentioned above include magnesium compounds and their complex salts represented by the general formula MgR7xX1y which are typified by magnesium compounds such as MgCl2 and Mg(OC2H5)2. Here, R7 is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, x1 is a halogen atom or an alkyl group having 1 to 20 carbon atoms, x is from 0 to 2, y is from 0 to 2, and x+y=2. The respective R7s and X1s may be the same or different.
Furthermore, examples of the organic carriers include polymers such as polystyrene, polyethylene, polypropylene, substituted polystyrenes and polyarylates, starch and carbon.
As the carriers which can be used in the present invention, MgCl2, MgCl(OC2H5), Mg(OC2H5)2, SiO2, Al2O3 and the like are preferable from the viewpoint of the easiness of morphology control and handling. The state of the carrier depends upon its kind and manufacturing process, but its average particle diameter is usually in the range of 1 to 300 xcexcm, preferably 10 to 200 xcexcm, more preferably 20 to 100 xcexcm.
If the particle diameter is small, the fine power of the polymer increases, and if the particle diameter is large, the coarse particles of the polymer increase, which causes the deterioration of a bulk density and the clogging of a hopper.
Moreover, the specific surface area of the carrier is usually in the range of 1 to 1000 m2/g, preferably 50 to 500 m2/g, and its pore volume is usually in the range of 0.1 to 5 cm3/g, preferably 0.3 to 3 cm3/g.
If either of the specific surface area and the pore volume of the carrier deviates from the above-mentioned range, a catalytic activity deteriorates sometimes. In this connection, the specific surface area and the pore volume can be calculated from the volume of an adsorbed nitrogen gas in accordance with a BET method [refer to Journal of the American Chemical Society, Vol. 60, p. 309 (1983)].
Furthermore, it is desirable that the above-mentioned carrier, when used, is calcined usually at 150 to 1000xc2x0 C., preferably at 200 to 800xc2x0 C.
In the case that at least one of the catalytic components is supported on the above-mentioned carrier, it is desirable that at least one of the catalytic component (A) and the component (B), preferably both of the catalytic component (A) and the component (B) are supported.
No particular restriction is put on a method for supporting at least one of the component (A) and the component (B), but there can be employed, for example, (1) a method of mixing at least one of the component (A) and the component (B) with the carrier, (2) a method of mixing, in an inert solvent, at least one of the component (A) and the component (B) with the carrier, after the carrier has been treated with an organic aluminum compound or a halogen-containing silicon compound, (3) a method of reacting the carrier, the component (A) and/or the component (B) with the organic aluminum compound or the halogen-containing silicon compound, (4) a method of mixing the component (B) or the component (A) with the carrier, after the component (A) or the component (B) has been supported on the carrier, (5) a method of mixing the carrier with a catalytic reaction product of the component (A) and the component (B), and (6) a method in which the carrier is allowed to coexist in the catalytic reaction of the component (A) with the component (B).
The thus obtained catalyst may be taken out as a solid by once distilling off the solvent and then used for the polymerization, or may be used for the polymerization as it is.
Moreover, in the present invention, the catalyst can be formed by carrying out the operation of supporting at least one of the component (A) and the component (B) on the carrier in a polymerization system. For example, a process can be employed which comprises adding at lease one of the component (A) and the component (B), the carrier and, if necessary, the organic aluminum compound of the above-mentioned component (C), further adding an olefin such as ethylene under atmospheric pressure to 20 kg/cm2, and then doing prepolymerization at xe2x88x9220 to 200xc2x0 C. for a period of 1 minute to 2 hours to produce catalyst particles.
In the present invention, a use ratio of the above-mentioned compound (B) to the carrier is preferably in the range of 1:5 to 1:10000, more preferably 1:10 to 1:500 in terms of a weight ratio, and a use ratio of the compound (A) to the carrier is preferably in the range of 1:5 to 1:10000, more preferably 1:10 to 1:500 in terms of a weight ratio.
If the use ratio of the component (B) or the component (A) to the carrier deviates from the above-mentioned range, the activity deteriorates sometimes. The average particle diameter of the thus prepared catalyst for the polymerization of the present invention is usually in the range of 2 to 200 xcexcm, preferably 10 to 150 xcexcm, particularly preferably 20 to 100 xcexcm, and the specific surface area of the catalyst is usually in the range of 20 to 1000 m2/g, preferably 50 to 500 m2/g. If the average particle diameter is less than 2 xcexcm, the amount of the fine powder in the polymer increases sometimes, and if it is more than 200 xcexcm, the coarse particles in the polymer increase sometimes. If the specific surface area is less than 20 m2/g, the activity deteriorates sometimes, and if it is in excess of 1000 m2/g, the bulk density of the polymer deteriorates sometimes. Furthermore, in the catalyst of the present invention, the amount of the transition metal in 100 g of the carrier is usually in the range of 0.05 to 10 g, particularly preferably 0.1 to 2 g. If the amount of the transition metal is outside the above-mentioned range, the activity deteriorates sometimes.
By supporting the component on the carrier as described above, there can be obtained the polymer having a high bulk density and an excellent particle diameter distribution which are industrially advantageous.
According to the preparation process of the polymer of the present invention, the employment of the above-mentioned catalyst for the polymerization results in a desirable accomplishment of the homopolymerization of an olefin, or the copolymerization of an olefin and another olefin and/or another homopolymer (i.e., copolymerization of different kinds of olefins, copolymerization of an olefin and another monomer, or copolymerization of different kinds of olefins and another monomer).
No particular restriction is put on the kind of olefin, but the xcex1-olefins having 2 to 20 carbon atoms are preferable. Examples of such xcex1-olefins include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene. Furthermore, the above-mentioned other olefin may suitably be selected from the above-mentioned olefins.
In the present invention, the above-mentioned olefins may be used singly or in a combination of two or more thereof. In the case that the copolymerization of two or more kinds of olefins is carried out, the olefins can optionally be combined. With regard to a use ratio of the olefins in such a case, for example, in the case that propylene and ethylene, or ethylene and an xcex1-olefin having 3 to 10 carbon atoms are subjected to the copolymerization, a copolymerization ratio (a molar ratio) between propylene and ethylene, or between ethylene and the xcex1-olefin having 3 to 10 carbon atoms is usually selected in the range of 99.9:0.1 to 0.1:99.9, preferably 99.5:0.5 to 75.0:25.0.
In the present invention, the above-mentioned olefin may be copolymerized with another monomer, and examples of the other monomer which can be used herein include vinyl aromatic compounds such as styrene, p-methylstyrene, isopropylstyrene and t-butylstyrene, straight-chain diolefins such as butadiene, isoprene and 1,5-hexadiene, cyclic olefins such as norbornene and 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, cyclic diolefins such as norbornadiene, 5-ethylidenenorbornene, 5-vinylnorbornene and dicyclopentadiene, unsaturated esters such as ethyl acrylate and methyl methacrylate, lactones such as xcex2-propiolactone, xcex2-butyrolactone and xcex3-butyrolactone, lactams such as xcex5-caprolactam and xcex4-valerolactam, and epoxides such as epoxypropane and 1,2-epoxybutane.
Incidentally, the catalyst for the polymerization of the present invention can be used in not only the polymerization of the above-mentioned olefins but also the polymerization of monomers other than the olefins.
In the present invention, no particular restriction is put on a polymerization method, and there can be used any of a slurry polymerization method, a gaseous phase polymerization method, a bulk polymerization method, a solution polymerization method and a suspension polymerization method, but the slurry polymerization method and the gaseous polymerization method are particularly preferable.
With regard to polymerization conditions, polymerization temperature is usually in the range of xe2x88x92100 to 250xc2x0 C. preferably xe2x88x9250 to 250xc2x0 C., more preferably 0 to 220xc2x0 C. Furthermore, a use ratio of the catalyst to the reactive material is such that a material monomer/the above-mentioned component (A) ratio (molar ratio) is preferably in the range of 1 to 108, more preferably 1 to 105. Furthermore, polymerization time is usually in the range of 5 minutes to 10 hours, and reaction pressure is usually in the range of atmospheric pressure to 200 kg/cm2G, preferably atmospheric pressure to 100 kg/cm2G.
Means for adjusting the molecular weight of the polymer includes the selection of kinds and amounts of catalytic components, the selection of the polymerization temperature, the decision of whether or not the polymerization is done in the presence of hydrogen, and the like.
In the polymerization, a polymerization solvent can be used, and examples of the polymerization solvent include aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane, aliphatic hydrocarbons such as pentane, hexane, heptane and octane, halogenated hydrocarbons such as chloroform and dichloromethane. These solvents may be used singly or in a combination of two or more thereof. Alternatively, a monomer such as the xcex1-olefin may be used as the solvent. In a certain polymerization method, the polymerization can be carried out under non-solvent conditions.
No particular restriction is put on the molecular weight of the thus obtained polymer, but an intrinsic viscosity [xcex7] (measured in decalin at 135xc2x0 C.) of the polymer is preferably 0.1 dl/g or more, more preferably 0.2 to 20 dl/g, most preferably 0.3 to 15 dl/g.
In the present invention, preliminary polymerization can be carried out in the presence of the above-mentioned catalyst for the polymerization. The preliminary polymerization can be done by bringing, for example, a small amount of an olefin into contact with the solid catalytic component, but no particular restriction is put on its manner and a known manner can be used. The olefin for use in the preliminary polymerization is not particularly limited, and the same olefins as enumerated above are usable. Examples of such olefins include ethylene, xcex1-olefins having 3 to 20 carbon atoms and mixtures thereof, but it is advantageous to employ the same olefin as used in the polymerization.
Furthermore, preliminary polymerization temperature is usually in the range of xe2x88x9220 to 200xc2x0 C., preferably xe2x88x9210 to 130xc2x0 C., more preferably 0 to 80xc2x0 C. In the preliminary polymerization, as a solvent, there can be used inactive hydrocarbons, aliphatic hydrocarbons, aromatic hydrocarbons and monomers. Above all, the aliphatic hydrocarbons are particularly preferable. In this connection, the preliminary polymerization may be carried out in the absence of any solvent.
In the preliminary polymerization, it is preferable to regulate conditions so that the intrinsic viscosity [xcex7] (measured in decalin at 135xc2x0 C.) of a preliminary polymerization product may be 0.2 dl/g or more, preferably 0.5 dl/g or more and the amount of the preliminary polymerization product per mmol of the transition metal component in the catalyst may be in the range of 1 to 10000 g, preferably 10 to 1000 g.
Next, the present invention will be described in more detail with respect to examples, but the scope of the present invention should not be limited to these examples.
In the examples and comparative examples, physical properties of polymers were measured as follows.
(1) Intrinsic viscosity [xcex7]
This was measured in decalin at 135xc2x0 C.
(2) Weight-average molecular weight (Mw) and number-average molecular weight (Mn)
Each of them was determined in terms of polyethylene by gel permeation chromatography (GPC) (device: Waters ALC/GPC 150C, column: TSK HM+GMH6xc3x972 made by Toso Co., Ltd., flow rate: 1.0 ml/min) at 135xc2x0 C. by the use of 1,2,4-trichlorobenzene as a solvent.
(3) Melting point
This was measured by DSC (differential scanning calorimeter) analysis.
Measurement conditions
First heating: From room temperature to 190xc2x0 C., at 10xc2x0 C./min, and maintained for 3 min
First cooling: From 190xc2x0 C. to room temperature, at 10xc2x0 C./min, a nd maintained for 3 min
Second heating: From room temperature to 190xc2x0 C., at 10xc2x0 C./min
(4) octene unit content (mol%)
This was measured by 1H-NMR.